


grab 'em by the horns

by Selador



Category: Final Fantasy XV
Genre: Alternate Universe - Succubi & Incubi, Alternate Universe - Supernatural Elements, Anal Sex, Cuddling & Snuggling, Horns, Human Nyx, M/M, Not Realistic Sex, Oral Sex, Succubi & Incubi, Succubi Make Sex Easier, Succubus Prompto, horny horned boy, they have sex and everyone is happy, virgin prompto
Language: English
Status: Completed
Published: 2017-11-11
Updated: 2017-11-11
Packaged: 2019-02-01 00:33:51
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,196
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12693384
Author URL: https://archiveofourown.org/users/Selador/pseuds/Selador
Summary: "Prompto gets turned into a succubus a little before his twenty-first birthday, which sucks for a lot of reasons, but the first and foremost being that he’s a fucking virgin."





	grab 'em by the horns

**Author's Note:**

  * For [kickingshoes](https://archiveofourown.org/users/kickingshoes/gifts).



> For the wonderful kickingshoes, who sent me prompts of "supernatural creatures au" and "nyx and prompto live in the same shitty apartment building" for some good old promnyx.
> 
> <3

Prompto gets turned into a succubus a little before his twenty-first birthday, which sucks for a lot of reasons, but the first and foremost being that _he’s a fucking virgin_.

It’s really not ideal, and his sire laughs at him when he tells him. “You’ll be fine,” he says. “You’ll know what to do.”

Except Prompto distinctly _doesn’t_ , but he goes to a bar near his house anyway to try to pick someone up.

He sits around awkwardly at the bar, sipping drinks that now taste weird and barely do anything for him because he needs to get his sustenance from sex now, and goes home alone without any success.

Prompto walks into his shitty apartment and goes straight to bed, miserable, tired, and hungry. As soon as he’s about to fall asleep, he hears his upstairs neighbor.

Moaning.

Having sex.

Something quivers inside of him, listening to his neighbor—something new and hungry that whispers to Prompto that he should go up there and join them.

Prompto takes his pillow and covers his ears.

It doesn’t help. He can feel it, in a way, and while it doesn’t make him not hungry, threads of their sexual energy help sustain him.

Or something like that. His sire wasn’t super helpful on that explanation.

Prompto doesn’t end up sleeping, and neither does his neighbor.

…

His neighbor is a handsome man with small tattoos on his face and every movement he makes exudes a preternatural sensuality that Prompto feels that he should have as a succubus and does not. He makes his mouth water and gut clench.

Prompto avoids him. He just wants to fall down to his knees in front of him and suck his dick dry, but that’s probably not a wise desire to follow.

The next night he tries a different bar, and he gets a guy talking to him, which is progress. The further the conversation progresses, the more the guy visibly loses interests, eventually leaving him behind without a phone number or anything.

Prompto goes home alone.

His neighbor is having sex.

Prompto spends another night awake. Listening, and wishing he were there.

…

If anything, Prompto’s attempts at seduction get worse from his hunger and desperation. He looks terrible, and he can’t maintain even a normal conversation.

He hasn’t eaten anything in days. Not since he was human.

Prompto can’t even stand going to the bars anymore, and he’s no good at them. He needs a different strategy.

The walls are so thin in his apartment, he can hear his neighbor upstairs moving around. Getting ready for another night out, find someone to hook up with, and bring them back for a night of sex.

Prompto gets up. He doesn’t have a plan, just walks barefoot out of his apartment and up the stairs, until he gets to the unit directly above his, and knocks.

His neighbor opens the door, expression mild and polite, an old, ripped shirt on and sweatpants hanging low on his hips.

Prompto begins to cry.

“Oh, shit,” his neighbor says softly. “Ah, um, you’re from downstairs, aren’t you? What’s wrong?”

Prompto cries harder, covering his face with his hands, and his neighbor swears. “Alright, come on,” he says, a hand pressing against Prompto’s shoulder and pushing him forward. It’s nowhere near sexual in nature, but Prompto’s so hungry that even that little bit of contact is better than nothing.

He walks inside his neighbor’s apartment, which is sparsely furnished and decorated. Briefly, Prompto wonders what his neighbor does--he barely hears him aside from late in the evening and during his nightly escapades.

But now Prompto’s being led to sit down his neighbor’s bed, while his neighbor takes the solitary chair in the room, because there is no couch or other sitting area.

He keeps sobbing, and his neighbor flutters around a bit, not quite sure what to do. He keeps asking things like ‘are you alright?’ and ‘did something happen to you?’ which is nice, but not helpful.

When he recovers enough to speak, he tells his neighbor, through hiccuping sobs, “I need you to teach me,” he has to stop because his lungs won’t listen to him and are too busy hiccuping for him to speak, “to seduce people.”

His neighbor’s expression flatlines. The concern and worry drop off for complete confusion and blankness. “I’m sorry, what?”

“I need to,” Prompto starts, trying to think of a normal explanation, a _human_ explanation, for needing to seduce people. “Um, did you know that some insects die if they don’t have sex?” he tries, and his neighbor’s face becomes stormy. Prompto changes track. “You seem to be really good at getting people to come home with you, I can hear you like. Every night.”

His neighbor is definitely angry, and he stands up. “Get out.”

“Wait!” Prompto yelps, scrambling away from his neighbor.

“You fucking creeper,” his neighbor yells. “What the _hell_? What the hell is wrong with you!”

“I’m a succubus!” Prompto yells, and then remembers that _the walls are fucking thin_ , and says more quietly, “I’m a succubus and I’ve never had sex!”

His neighbor snorts, and says, “Yeah, fucking right! And I’m a fucking werewolf!”

“Oh, god, are you?” Prompto says, but a werewolf would be able to smell him, wouldn’t they? “‘Cause that would make this so much easier.”

His neighbor stops, stares at him, and shakes his head. “What fuck is wrong with you?” he repeats. “You don’t go to your neighbor and tells them that you can hear them having sex every night. Dude, I _know_ the walls are super thin, but, shit. Don’t _say_ anything about it,” his neighbor says, lip curling. “And what the fuck was that about _dying_ without _sex_? You know that doesn't fucking happen, right?”

“I…” Prompto tries to think a way to explain that doesn’t make him sound as inhuman as he is. “I’m just so _hungry_.” That was not it. That was not it at all.

Something weird happens to his neighbor’s face, before it resettles into cold, hard lines. “Yeah, you’re leaving. _Now_.” He stalks forward to Prompto, face determined and steely, and Prompto fears that he’s going to force him out with violence.

He stumbles backwards, his neighbor grabs his arms, and wrenches him towards the door.

Prompto fights, gets too distracted, and his glamor drops.

If it had been any other situation, the expression on his neighbor’s face would have been funny. Wide-eyed and open mouth, he is the very picture of stunned, and it’s the first time in all of this that Prompto’s seen him less than sure and composed.

Unfortunately for Prompto, his wide eyes are focused on Prompto’s newly revealed horns--and after a few seconds, dart down to the claws on his hands. Prompto keeps his mouth firmly shut so he won’t see the fangs.

“Oh my gods,” his neighbor says. “Oh my _gods_ . What the fuck? What the _fuck?_ ”

“Don’t freak out,” Prompto pleads.

His neighbor stares at him, and says, voice slightly higher than it was before. “Don’t freak out?” he repeats, freaking out. “Don’t _freak_ out? _What the fuck are you_?”

“I already told you!” Prompto says, and knows the instant from his neighbor’s rapidly paling face that he can clearly see his fangs. “I’m a _succubus_ !”

“No, you’re not!” His neighbor says, voice rising in volume. “You can’t be, that’s not _real_.”

Prompto reaches up and lightly touches one of his horns. He doesn’t know what more he could say as evidence than his own fucking horns.

On the plus side, his neighbor isn’t trying to push him out of the flat anymore. He’s keeping a bit of a wide berth away from him, in fact.

“Those can’t be real,” his neighbor says flatly.

“They are real,” Prompto says.

“They can’t be,” Nyx says. “Can I touch them?”

“What?” Prompto says in reflex, before the question catches up to him. He tugs on his horn himself, and feels it pull at his skull. He thinks about his neighbor touching them, pulling on them, holding them--and says with a dry mouth, “Yeah.”

His neighbor tentatively approaches him, and when he reaches out to Prompto’s head, Prompto tilts his head down for better access. It doesn’t quite matter though--his neighbor is tall enough that he can reach Prompto’s curling horns no problem.

When his fingertips lightly touch Prompto, he can feel the pressure through nerve endings he didn’t even have before a week ago.

“Okay,” his neighbor says faintly. “Horns. Alright.”

“Yeah,” Prompto says. His neighbor is close enough that he can smell him, leather and warmth and... arousal. “Dude,” he says, “do you have a boner right now?”

His neighbor looks down at him. “You are _literally_ a succubus, aren’t boners your kind of thing?”

“I mean, _yeah_ ,” Prompto says, shifting in place, “but, uh, I’ve never done this before?”

“I thought you said you need this to… succubi need sex to live, right? It’s sustenance?” his neighbor says. “Okay, that makes that whole shit about being _hungry_ slightly less creepy, but it’s still pretty creepy.”

“You’re the one with a _boner_ ,” Prompto mutters, hunching his shoulders.

“You’re a sex demon, don’t judge,” his neighbor says affronted. “Look, okay--what’s your name?”

“Prompto,” he says. “Um--I live downstairs.”

“Yeah, I know, I’ve seen you around. I’m Nyx,” he says. “Why does a sex demon live in such a shitty building, anyway?”

“Yeah, well. I haven’t been a sex demon for very long,” Prompto says. “It’s kind of a new thing.”

“A new thing,” Nyx repeats. “How is it a new thing?”

“I was only turned like a week ago,” Prompto says. Nyx still smells _good_ , but Prompto doesn’t know how to do this. He thinks of his sire’s stupid face and hopes he fucks himself.

“Turned, like a vampire?” Nyx asks. “Wait, when you say you’re _hungry_ , do you literally mean you eat people you have sex with?” The arousal begins to fade, replaced by a curdling scent of fear. “Or--absorb their life forces, or something?”

“No! I don’t _eat_ them, I feed off the energy that’s made through sex--or I’m supposed to, but _I’ve never done this before_!” Prompto exclaims. He can’t pick at his hands or his skin with claws, but he can reach up to tug worryingly at his horn.

“Wait. Okay, wait a minute, when you say ‘never done this before,’ I thought you meant the _succubus_ thing, but do you mean _sex_ ?” Nyx asks. He sits down on the bed. “Are you telling me you’re a sex demon _and_ a virgin?”

Prompto hesitates, which is answer enough, but nods. He can’t own up to it verbally, because if he felt inadequate and ashamed about his status as a virgin while he was _human_ , there’s no words for how shitty he feels as a _virgin sex demon_.

“Ah, shit, man, I’m not trying to make fun of you,” Nyx says, leaning back onto his hand, still sitting on his bed. It’s less aggressive than he was before, and the fear dissipates from the air in the room. “I’m just--I have questions, okay?” he says, running a hand through his hair. Prompto watches the movement, but tries not to.

“More questions?” Prompto asks.

“Yeah, I mean--look,” Nyx says, “you want me to help you… seduce someone so you can feed off of them?”

“It won’t hurt them,” Prompto protests, weakly.

“You’re sure about that?” Nyx asks, raising his eyebrows incredulously.

“Yeah,” Prompto says. What he can and can’t do, what _harm_ he’s capable of like this, is something his sire did at least go over. He _could_ really hurt someone--and kill them--if he doesn’t stop at just sucking their dick dry and keep going. But his sire compared such a thing to be _gluttonous_ and unnecessary, and Prompto really doesn’t want to kill anybody. “I’m certain.”

Nyx’s finger taps against the covers of his bed, and he says, “Okay. Come here.”

The command doesn’t really sink in right away, and neither does the implications. “What?”

“Well,” Nyx says, leaning on his arm, giving Prompto a slow once-over. “We _could_ go out and find someone for you to have sex with.”

“I thought that’s what we were going to do,” Prompto says, flushing and not quite able to stop looking the line of his neck.

“But I’m here, willing, and dying to know if sex with a succubus will live up to the myths,” he says, and his eyes drop very deliberately to Prompto’s crotch.

Heat rushes to Prompto’s face. “Um--”

“I’m just as much as a stranger as anyone you’d meet,” Nyx says. “And I don’t really want to help you find someone for you to feed on.”

“But--you’re fine with me feeding on you--?”

“So long as you’re certain it won’t actually hurt me,” Nyx comments, lying back flat on the bed. Prompto eyes the curve where his neck meets his shoulder, where his shirt rides up revealing a slip of skin on his abdomen.

Prompto steps forward. Not quite thinking of it, he lets his claws fade away with a glamor. “I’m sure.”

Without looking at him, Nyx waves him forward. “Come over here then.”

Prompto takes another step, and then another, and then he’s standing over the bed, looking down at Nyx’s relaxed form.

Nyx cracks open an eyelid. “So how do you want to do this?”

“Um--” he says, unable to pull his eyes away from the line of Nyx’s body. He’s so _relaxed_ , it’s obscene.

“You gonna make me get up again?” Nyx says, and Prompto lays his knee on the bed, leaning down until he’s hovering just above Nyx’s face. Nyx watches him as he does, smirks a bit, and then reaches up to pull him down into a kiss.

Prompto moans, and falls fully on top of Nyx. He shivers when a calloused hand grip his horn, and he feels a shot of heat go through him when Nyx rolls them over so he’s on top.

“Oh,” Prompto says, eyes wide and feeling unfamiliar heat between his legs. “Oh, oh, _okay_.”

“Hm, what is it?” Nyx asks, between kissing up his jawline, each kiss making him hotter and--and more _energized_ , okay, is that the feeding thing?

His arms brace on either side of his head, and Prompto quivers at being so thoroughly blanketed. Nyx trails down his jaw to his neck, licking and nipping, but stopping at his shirt collar.

“Clothes--clothes, we need to take off our clothes,” Prompto whispers urgently, tugging at Nyx’s shirt. Nyx obligingly leans away to take off his clothes--but Prompto can’t stand losing those lips on his skin, and follows. He grips at Nyx’s shirt as he straightens, mouthing at his skin, lifting himself up onto his knees.

“ _Oh_ ,” Nyx says, and then Prompto moves back to his mouth. Nyx moans, but says when Prompto moves away, “I thought you wanted less clothes.”

“Yeah,” Prompto says, “Less clothes,” and he reaches down to help tug Nyx’s shirt off, only breaking away from his face he he absolutely has to. He grasps his shoulders and leans down to his chest as Nyx fumbles with his pants and kicks them off.

“Your turn,” Nyx says, sliding his hands up Prompto’s abdomen, callouses catching on the soft skin, pulling up his shirt with it. He doesn’t wait for Prompto to remove himself from Nyx’s skin, just pulls the shirt over his face and off. It gets caught on one of Prompto’s horns for a moment, but he pulls until it rips, and then it’s across the room and out of the way. “Pants,” Nyx pants

Right, pants. Prompto can get on board with that, because if he has his pants on, _how_ can Nyx fuck him until he’s full and sated?

He slides off the bed and away from Nyx for-- _too long_ \--a moment to pull his pants down, but tackles Nyx back onto the bed before his pants are fully unhooked from his ankles. Prompto thrashes his leg until it’s off, and works his way down Nyx’s torso until he’s at his dick.

He licks it in one long stripe, and Prompto wants to take it all into his mouth, so he does.

Nyx swears, and one of his hands finds back to Prompto’s horns, which he strokes before getting a good hold on it. _Oh_ , Prompto thinks.

There’s a brief moment where Prompto wonders what the _fuck_ he’s doing. He’s never _done_ this before but--he wants is _so bad_.

“Hang on--hang on,” Nyx gasps, pulling a bit more at Prompto’s horn. “If this is--this is your first time.” He moans, interrupted by Prompto swallowing around him. “ _Fuck_. We should--do this differently.”

Prompto hums, pulling away with a broad, longing lick. “Do what differently?” he asks, out of breath himself. But he feels _great_ , he had no _idea_ it would feel this good--

Ah. Right. Succubus.

That probably has something to do with it.

“First timers,” Nyx says, propping himself up to a seated position, and pulling Prompto onto his lap. “Deserve special treatment.” He thrusts up a bit, sliding his hot cock in the cleft of Prompto’s ass. Prompto shudders and plants his feet by Nyx’s hips, lifting himself up.

Prompto lines up so the cockhead presses against his entrance, reaching behind him to help, and lowers himself down just as Nyx says, “Wait--” before cutting off with a loud moan. Prompto meant to go slowly, since he _knows_ that it can hurt otherwise but he’s warm and aching for it, and it doesn’t hurt at all. It felt so good, just having that tip in, the tease of fullness that he suddenly so desperately craves, that slides down until it’s all the way in.

“Oh my god,” Nyx says. “Oh my _god_.” Prompto lets himself relax on Nyx’s lap for a moment, and Nyx pulls him flush against him when he wraps his arms tightly around him and burying his face into the crook of Prompto’s neck. Prompto grips Nyx’s shoulders and lifts himself up, before slamming back down.

Nyx breathes hot and heavy against his collarbone while Prompto leverages himself into a fast grind. He pulls Nyx in flush against him and grinds up for the friction of his hard abs against his dick, along with the sweet fullness inside of him.

Nyx licks and sucks at his neck, but at some point it devolves to mindless mouthing of his skin as Prompto grinds harder until Nyx’s moans join his own whimpers and he comes, heat spreading inside of him.

And there’s a flush of such distinct satisfaction and pleasure that Prompto comes, thighs trembling, all over Nyx’s chest.

He leans into Nyx’s neck, breathing in the heat and sweat between their bodies. Prompto feels--better, no longer craving and miserable and two steps away from desperate, but he’s still so hard.

“Damn--sex demon doesn’t disappoint,” Nyx says, laughing into his neck.

Prompto swallows. He still feels hungry, and uncomfortably _hot_ , and he just wants Nyx to throw him down on the bed and _go again_ , but he asks, “Are you okay?”

"I’m good,” Nyx mutters. “Better than good. How are you?”

“Better,” Prompto whispers. He tries to resist for a moment, the appeal of tasting the skin pressed against his face, and loses. He licks.

“ _Oh_ ,” Nyx says. “Do that again.”

Prompto obliges, licking a stripe up Nyx’s neck, kissing his jawline to his lips. Hands grip his hips, and Prompto lifts himself up and off, sighing a bit in disappointment when he’s empty.

“Oh, okay,” Nyx says, when his mouth isn’t occupied. “I think--I can’t usually get it up so fast right after, is that because of you?”

“I think so,” Prompto says, even though he doesn’t really know, but that’s seems _much_ too convenient to be a coincidence. “Are you ready?”

“For round two? Hell, let’s do it.” Prompto wastes no time in pushing him down, and Nyx spreads out his legs for him.

Prompto’s protest is muffled in a kiss, and he has to force himself to pull away to say, “No, I would--I want you to fuck me. Please.”

“Yeah,” Nyx says. “Yeah. Okay,” and Prompto finds himself flipped over so Nyx is blanketing his entire body, pressing him down into the mattress.

Prompto’s not as desperate now. He doesn’t have that gnawing hunger, and he burns for Nyx, but he’s not as distracted as he was, when a tease of skin did him in. He smooths his hands up Nyx’s back, revels in the firm muscles and wondering over the scars he finds there. Nyx’s hand traces his arm, lightly holding down his wrist, before he brings it up to press a kiss to it.

“How do you want this? Like this?” Nyx asks, thrusting his dick against Prompto’s. “Or--on your stomach?”

The idea of being fucked into the mattress by Nyx, fast and hard, billows into Prompto’s mind. “Stomach,” he answers.

Nyx lifts himself up on his arms, enough for Prompto to flip over. A strong hand pushes his head down to the bed and his entire body goes down. “That okay?” Nyx asks, his other hand at his hip.

Prompto nods, turning his head so he can breathe even though his horn rests oddly against the bed, the hand in his hair pulling.

“Good,” Nyx says, and Prompto feels the cockhead against his entrance for a second before Nyx enters him with one thrust.

The hand in his hair tightens, almost painfully, holding him in place and Nyx fucks him hard. It’s much harder and _better_ than the grinding before--he can’t stop the whimpers from falling out, every time at the onslaught.

Prompto writhes a bit, and Nyx falls down on top of him, hooking his arms around him, and keeps going. Prompto moans and whines, as Nyx smooths his hand down his arms and kisses the nape of his neck.

Nyx comes, like before, with a moan. And like before, it’s that moment of a warmth spreading beyond what can be explain through sex that bring Prompto over the edge.

After they’re both spent, Nyx collapses on top of Prompto like a warm, heavy, human blanket. Prompto turns to his side a bit, and is treated to a warm, lazy kiss on his cheek. “I think that’s my limit,” he says.

Prompto hums agreeably. He wouldn’t say no to another round, but he feels _great_. Sated. Full. Happy.

Nyx pulls out of him, and he can’t stop one more whimper, causing Nyx to rub his lower back soothingly. He cleans them up, and crawls back into bed around Prompto. Prompto thinks idly he ought to hide his horns away, but one of Nyx’s hands come up to trace the ridges, and it sends little shivers down his spine.

“So,” Nyx says, as they doze in and out. “How often do you need to feed?”

Prompto considers. “I think my sire said every day. Maybe every other day?” He shrugs as best he can lying down and in a man’s arms. “Apparently, a lot of us just have one or two partners that we consistently go to for sex.”

"Hm," Nyx says consideringly. “Like a relationship, or… just for sex?”

“Um,” Prompto says, tensing his brow. “Both, I think?”

“Well,” Nyx says, brushing his fingers against Prompto’s face. “Come on up any time you need to fuck. ‘Cause I’m down.”

Prompto chuckles, and also relaxes. The desperation of the past days make him wince, and he never wants to get to that point again. “Thank you. I’ll work on--finding someone else, so I don’t need to come here and bother you every day.”

“Yeah,” Nyx says before they fall asleep.

…

Prompto never finds another person. He goes to Nyx every night for a couple of weeks, and he asks him, “Hey, want to catch a movie tomorrow?”

“What?” Prompto asks. He’s drinking coffee--turns out, caffeine still affects succubi.

“Movie. Want to go with me?” Nyx asks. “You don’t have to, but I thought it might be fun before or after our _other_ activities,” he adds, with a wink.

Prompto flushes. He’s a _sex demon_ , why does he still blush so easily? Having sex hasn’t made him any cooler or smoother at _all_. “Yeah, sure. Movie sounds good.” He goes back to his phone game, almost at the end of the level, before he has a realization. “Wait. Do you mean like a date?”

“It could be,” Nyx answers. He doesn’t shy away from the question, but looks Prompto in the eye with his back straight. Prompto’s phone dings with a downer melody, letting him know that he’s lost this level. He ignores it. “It doesn’t have to be. I’ll keep being your fuck buddy regardless. But I was thinking that maybe we should give it a shot.”

Prompto opens his mouth, warm all over that has nothing to do with sex or being a succubus. “Yeah. Yeah, I’d like that,” he says. “I’d really like that.”

**Author's Note:**

> BONUS:
> 
> Nyx realizes only after Prompto leaves after that first night that his lube is still unused and and unopened in his drawer, but they sure as hell had lubrication during sex.
> 
> He considers the lube and thinks about the smooth slide of last night’s fuck. But they didn’t use lube.
> 
> Nyx tosses it back into the drawer, and decides to appreciate the convenience of having sex with a succubus.
> 
> (When Nyx said "wait" during sex, he was going to say that they need to prepare Prompto. Prompto didn't need preparation though.)


End file.
